Neuroscience of Addiction – What We Do Know
When a drug enters the body, it interacts with the brain. Different addictive substances affect the brain in different ways, although most drugs target the brain’s reward system by releasing large amounts of a neurotransmitter called dopamine. Dopamine has a large impact on many important functions of the brain such as emotions, movement, motivation, and pleasure.
Neuroscience and the role of dopamine
Recent research in neuroscience indicates that the role of dopamine in the brain may be designed to help us make predictions about and learn from the environment. After a drug is consumed, a surge in dopamine occurs and a part of the brain called the anterior cingulate cortex, which is involved in learning from the environment, interprets the dopamine surge as a reward that was better than expected. This ‘larger than expected’ release of dopamine signals that something important has occurred that needs to be remembered. Drugs have a much larger dopamine release and impact on the brain than naturally rewarding experiences such as food, sex or exercise. As such, the brain prioritises seeking and using drugs to receive the new level of dopamine response it has experienced.
How the brain encourages addictive behaviours
The prediction and learning processes associated with unexpected releases of dopamine impact motivation and drug-seeking behaviour. The addicted brain engages in increased attention towards drugs over and above natural rewards. In other words, it becomes harder to seek out pleasure from experiences that were previously rewarding.
When a drug is withdrawn from the body (detox) it results in a large drop in dopamine levels. The brain interprets this dopamine drop as an unpleasant outcome that must be corrected. Increased attention is then directed towards drugs, and drug-seeking behaviour continues in order to escape from the unpleasant feelings and the need to learn from the environment.
The neuroscience of addiction and higher-order brain functions
Not only do drugs target automatic reward circuits and motivation processes in the brain, studies in neuroscience have shown they also impact the frontal lobes of the brain, which are responsible for decision-making, flexible thinking, memory, and impulse control. It’s these functions that become weakened and make it hard to stop using drugs or alcohol even when the drug user has a strong desire to quit. During adolescence, the frontal lobes are still developing which places young people at an even higher risk of addiction.
Is addiction a choice?
Whilst the initial decision to use drugs or alcohol is voluntary, neuroscience tells us that the ability to choose to stop is not as simple. A combination of the pleasurable response, reward system activation, motivation processes, and weakened executive functions result in a pattern of compulsive drug using that is almost impossible to control. This means that addiction is a disease, not a choice.
Can the brain recover?
Neuroscience provides strong evidence that addiction interferes with healthy brain functioning and can have harmful effects with continued substance abuse. Addiction is a lifelong disease, however, studies in neuroscience indicate that the harmful effects on the brain are treatable and the brain is capable of rewiring when daily recovery practice is maintained. The first step to recovery is seeking professional help. For more information call Arrow Health on 1300 295 989.
- Bourzac, K. (2015). Neuroscience: Rewiring the brain. Nature, 522, S50-S52. doi: 10.1038/522S50a
- Munro, M. (2015). The hijacked brain. Nature, 522, S46-S47, doi:10.1038/522S46a
- National Institute on Drug Abuse. (2015, July 29). Addiction Science. Retrieved from https://www.drugabuse.gov/related-topics/addiction-science
- National Institute on Drug Abuse. (2018). Drugs, brains and addiction: The science of addiction. Retrieved from https://www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction/preface